Inert gas absorption refrigeration



Jan. 16, 1951 w. G. KOGEL 2,533,013

INERT GAS ABSORPTION REFRIGERATION Filed May 31, 1946 IN VEN TOR.

Patented Jan. 16, 1951 INEBT GAS ABSORPTION REFRIGERATION Wilhelm Georg Kiigel, Stockholm, Sweden, as-

signor to Aktieboiaget Elektrolux, Stockholm, Sweden, a corporation of Sweden Application May 31, 1946, Serial No. 673,669

4 Claims.

This invention relates to refrigeration and more particularly to absorption refrigeration apparatus of the pressure equalizin type.

It is an object of the invention to provide an improvement to obtain better liquid circulation in heat operated absorption refrigeration apparatus of this type having a vapor-liquid lift tube or pump which receives absorption solution from an absorber through a passage of a liquid heat exchanger, the inlet of the lift tube or pump being at a lower level than the outlet of the liquid heat exchanger passage from which solution flows to the lift tube.

The above and other objects and advantages of the invention will be better understood from the following description taken in connection with the accompanying drawing forming a part of the specification, and of which:

Fig. 1 is a fragmentary view of absorption refrigeration apparatus embodying the invention; and

Figs. 2 and 3 are fragmentary views of parts similar to those shown in Fig. 1 illustrating further embodiments of the invention.

In Fig. 1 reference numeral II! denotes a tube acting as a flue which is essentially arranged in a vertical direction and in the lower mouth of which a heat source, not shown, is adapted to be applied. Along a generatrix common with the tube or flue Ill and thermally connected thereto, as by welding, extends a conduit II which forms the boiler proper of the apparatus. The conduit H, which is closed at its lower end and at its upper end communicates with a vapour conduit I2 leading to the condenser of the apparatus, not shown, contains solution having a relatively poor or weak concentration of refrigerant in an absorbent, such as ammonia in water, up to a level indicated at I3. On the opposite side of the tube Ill from the conduit I l and alongside the former another conduit I4 is arranged which contains solution richer in refrigerant than that in the boiler conduit II. As shown, the conduit I4 up to a level located somewhat above the liquid surface denoted at I 5 may be formed of relatively thick pipe, while the upper part thereof, which communicates with the vapor conduit I2 and serves as a vent, suitably may be formed of comparatively thin pipe. A lift tube or pump pipe It, which is thermally connected to the flue id, as by Welding, is connected at its lower end to the lower end of the conduit I l and its upper end at H to the boiler conduit II at a region which is some distance above the liquid level therein, The lift tube or 2 pump pipe is is of such diameter that vapor or gas bubbles formed therein due to heating of liquid by the flue I13 cannot freely pass liquid, so that lifting or pumping of liquid by gas or vapor lift action will be effected.

A liquid heat exchanger I8 in the form of a coil having essentially even pitch is disposed about the flue I8 and provides vertically extending paths of flow for solution rich and poor, respectively, in refrigerant. The inner pipe I9 of the exchanger is on one side by way of a conduit 26 connected with the absorber vessel 2|, which contains absorption solution rich in refrigerant. The upper end of the pipe I9 is connected to the conduit I4 which, as clearly shown in Fig. 1, is separated from the flue ID. The conduit I I communicates by way of a conduit 22, the outer pipe 23 of the heat exchanger and a stand pipe 24 with an absorber (not shown), which may be air"- cool-ed and suitably formed of a pipe coil, into which solution pumped into the boiler conduit I I passes by gravity flow.

As has been already mentioned, the conduit II forms the boiler proper in which, during operation of the apparatus, the refrigerant concentration of the solution gradually decreases in a downward direction toward the lower end of the boiler. The solution poor in refrigerant is withdrawn from the boiler II through the conduit 22 and flows through the heat exchanger I8 and conduit 24 to the absorber in which, in a known manner, the solution absorbs refrigerant vapours out of a gas mixture formed in an evaporator, not shown. During its passage through the liquid heat exchanger I8 the poor or weak warm solution gives up heat to the rich solution passing from the absorber vessel through the inner pipe is of the exchanger, thereby preheating the rich solution before it enters the conduit I4.

As will be clear from Fig. 1, the liquid tube or pump pipe I6 extends downwardly from the upper end of the liquid heat exchanger I8, and, instead of forming a direct continuation of the inner pipe I9 of the liquid heat exchanger, the pump pipe is connected to the lower end of the conduit Hi. It is highly advantageous to provide an arrangement like that shown and just described because of the low position at which the heat source is placed in the lower heat input end of the heating flue it. If this were not done and the pump pipe I 5 extended upwardly from the region at which the inner liquid heat exchanger pipe i9 is connected to the conduit I 4, the liquid reaction head under which solution is raised r lifted in the pump pipe by vapor lift action would be too small. Further, the heat supply to the pump pipe It would be inadequate, so that unsatisfactory pumping of liquid would result.

In the arrangement provided solution fiowing through the inner pipe [9 of the liquid heat exchanger passes into the conduit l4 and moves downwardly therein, and thence upwardly in the pump pipe I6 to a level approximately at the level of the solution in the absorber vessel 2|. In the embodiment of Fig 1, it is necessary to provide a vent connection from the upper end of the conduit M, as to the vapor conduit l2, for example, as previously described.

By thermally spacing the conduit Hi from the flue tube H3 according to the invention an advantage is obtained in that the refrigerant concentration of the solution streaming downwardly in conduit [4 will not appreciably decrease, so that the pump pipe It will receive relatively rich solution. In this way an intensive distillation of refrigerant will take place in the pump pipe It so that solution will be pumped or raised more effectively by gas or vapor lift action. However, the solution raised to the boiler level will be comparatively rich compared to the concentration desired for absorption of refrigerant vapor in the absorber of the apparatus. Therefore, according to the invention the conduit l l is arranged in thermal relation with the fiue i9 and heated by 1 the latter, the refrigerant concentration of solution therein due to distillation of refrigerant, thus being adapted to a concentration suitable for the absorption function when the solution passes from the conduit ll through conduit 22 and flows through the liquid heat exchanger and the conduit 24 to the absorber. t will be seen that the connection 22 communicates with the conduit Ii so that the lower part thereof forms a liquid pocket below the region solution passes from the conduit ll into the connection or conduit 22.

By arranging the conduit II, into which the pump pipe Hi delivers liquid, in heat conductive relation with the fine tube Hi, the solution fiowing therefrom into the liquid heat exchanger i8 is on entry at a temperature which is at least as high as that of the solution pumped into the conduit l I.

Tit may in many cases be advantageous to thermally space the lower part Of the boiler l i from the flue tube iii, as illustrated in Fig. 2. In this way all heat given up by the heat source within the lower heat input region or zone of the boiler aggregation is supplied to the pump pipe 16 which is welded to the tube l0, thus improving the pumping of solution effected in the pump pipe 16.

In other cases, when the resistance in the pump pipe I6 is greater than that of the conduit [4, there will be a likelihood of the liquid flowing back from the pump pipe into the conduit M. This inconveience may, however, be overcome by arranging the lower part of the pump conduit 56 in the form of a coil which is out of contact with the flue tube, so that sufficient re sistance to back-fiow will be established.

The invention is not to be limited to the embodiments shown and described but may be varied in several respects within the scope and spirit of the invention, as pointed out in the following claims. However, thi application and copending application Serial No. 568,269, filed December 15, 1944, contain common subject matter and subject matter not claimed herein is being claimed in the earlier filed copending application.

I claim:

1. In an absorption refrigeration system of the inert gas type including a refrigerant vapor supply line, an absorber, a liquid heat exchanger, a vapor expulsion unit comprising an upright heating tube, a first upright conduit thermally separated from said tube, a second upright conduit in thermal relation with said tube, said vapor supply line being connected to receive vapor from the upper ends of said first and second conduits, a lift pipe communicating with the lower part of said first conduit and the upper part of said second conduit, the aforesaid parts being so connected in the system that solution flows in an unbroken stream from the outlet of said absorber through said heat exchanger and first conduit into the lower end of said lift pipe and forms a liquid column in said first conduit having a liquid surface level which is above the highest point of said heat exchanger, and solution entering from said lift pipe forms a liquid column in said second conduit from which solution fiows through said heat exchanger to the inlet of said absorber, and said lift pipe having a part thermally connected to said heating tube in a zone extending between the liquid surface level in said first conduit and the lowest point of said heat exchangerto cause expulsion of vapor from solution in said pipe and raise liquid therein by vapor lift action under the influence of a reaction head formed by the liquid column in said first conduit, the lower region of the zone of said heating tube in thermal relation with said lift pipe being thermally separated from the lower part of said second conduit.

2. In an absorption refrigeration system of the inert gas type including a refrigerant vapor supply line, an absorber, a liquid heat exchanger, a vapor expulsion unit comprising an upright heating tube, a first upright conduit thermally separated from said tube, a second upright conduit in thermal relation with said tube, said vapor supply line being connected to receive vapor from the upper ends of said first and second conduits, a lift pipe communicating with the lower part of said first conduit and the upper part of said second conduit, the aforesaid parts being so connected in the system that solution flows in an unbroken stream from the outlet of said absorber through said heat exchanger and first conduit into the lower end of said lift pipe and forms a liquid column in said first conduit having a liquid surface level which is above the highest point of said heat exchanger, and solution entering from said lift pipe forms a liquid column in said second conduit from which solution fiows through said heat exchanger to the inlet of said absorber, and said lift pipe having a part thermally connected to said heating tube in a zone extending between the liquid surface level in said first conduit and the lowest point of said heat exchanger to cause expulsion of vapor from solution in said pipe and raise liquid therein by vapor lift action under the influence of a reaction head formed by the liquid column in said first conduit, the lower part of said lift pipe being of coil shape and out of contact with said heating tube.

3. In an absorption refrigeration system of the inert gas type including a refrigerant vapor supply line, an upright heating fiue having a lower heat input end, a circuit for circulation of absorption solution including an absorber, a liquid heat exchanger and a vapor expulsion unit comprising a first upright conduit, a first connection including said heat exchanger for conducting solution from the outlet of said absorber to said first conduit, a second upright conduit in thermal relation with said flue, a second connection communicating with said second conduit so that the lower part thereof forms a liquid pocket below the region solution passes from said second conduit into such connection, said vapor supply line being connected to receive expelled vapor from said second conduit, a lift pipe which is connected at its lower and upper ends to said first and second conduits, respectively, said first connection being so formed that said first conduit contains a liquid column whose liquid surface level is above the highest point of said liquid heat exchanger and which is in communication with the outlet of said absorber by an unbroken liquid body, and said lift pipe having a part in thermal relation with said flue along a zone extendin downwardly below the highest point of said heat exchanger to cause expulsion of vapor from solution in said pipe and raise liquid therein by vapor lift action under the influence of a reaction head formed by the liquid column in said first conduit, said liquid heat exchanger being in the form of a coil disposed about said heating fiue and both said first and second conduits.

4. In an absorption refregiration system of the inert gas type including a refrigerant vapor supply line, an upright heating flue having a lower heat input end, a circuit for circulation of absorption solution including an absorber, a liquid heat exchanger and a vapor expulsion unit comprising a first upright conduit, a first connection including said heat exchanger for conducting solution from the outlet of said absorber to said first conduit, a second upright conduit in therlution passes from said second conduit into such connection, a lift pipe which is connected at its lower and upper ends to said first and second conduits, respectively, said first connection providing a path through which solution flows in an un- {broken stream from the outlet of said absorber through said heat exchanger and first conduit "into the lower end of said lift pipe and forms a liquid column in said first conduit having a liquid surface level which is above the highest point of said liquid heat exchanger, and said lift pipe having a part in thermal relation with said flue along a zone extending downwardly below the highest point of said heat exchanger to cause expulsion jof vapor from solution in said pipe and raise liquid therein by vapor lift action under the influenoe of a reaction head formed by the liquid 1 column in said first conduit.

WILHELM GEORG KGGEL.

file of this patent:

- Number FOREIGN PATENTS Country Date Great Britain Dec. 28, 1936 Great Britain Dec. 31, 1943 

